Apparatus for reporting reception result of packets in mobile communication system

ABSTRACT

Disclosed is a receiver for configuring a Block Acknowledgement (BA) frame in a wireless communication system for acknowledgement of a data transmission from a transmitter. The receiver receives a Block Acknowledgement Request (BAR) frame in the data transmission from the transmitter and determines an overall size of a bitmap for the BA frame from the BAR frame to acknowledge the data transmission. The receiver configures the BA frame of the response to include the bitmap having the determined overall size, and transmits the configured BA frame to the transmitter. The bitmap of the BA frame includes bits representing reception results of packets of the data transmission received from the transmitter.

PRIORITIES

This application claims the benefit under 35 U.S.C. § 120 of and is acontinuation of co-pending U.S. patent application Ser. No. 11/202,895titled “Method for Reporting Reception Results of Packets in MobileCommunication System” filed in the United States Patent and TrademarkOffice on Aug. 12, 2005, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application Ser. No. 60/607,610 titled“Method for Reporting Reception Results of Packets in MobileCommunication System” filed in United States Patent and Trademark Officeon Sep. 7, 2004 and the benefit under 35 U.S.C. § 119(e) of KoreanApplications Nos. 2004-64049 and 2005-44645 filed in the KoreanIndustrial Property Office on Aug. 13, 2004 and May 26, 2005,respectively, which the contents of each of which were incorporatedtherein by reference. U.S. patent application Ser. No. 11/202,895 isexpressly incorporated herein by reference in its entirety for allpurposes.

BACKGROUND

1. Field of the Invention

The present invention relates to a bitmap structure for reportingreception result of packets applying a retransmission technique and amethod for transmitting/receiving the reception result in a mobilecommunication system.

In general, a radio channel can cause errors in transmitted packetsunder the influence of multi-path fading, interferences among users,noises, and so forth. A solution to this problem includes a ForwardError Correction Code (FEC) scheme in which the probability of erroroccurrence is lowered by additionally sending redundant information, anAutomatic Repeat Request (ARQ) scheme in which, when errors occurs,retransmission of packets where the errors have occurred is requested,and a Hybrid Automatic Retransmission Request (HARQ) scheme whichcombines both the schemes.

In the ARQ scheme, a receiver uses an Acknowledgment (ACK)/NotAcknowledgment (NACK) signal for notifying a transmitter of whether ornot received packets are erroneous. The ACK signal confirms to thetransmitter that the receiver has received the corresponding packets. Incontrast , the NACK signal confirms to the transmitter that the receiverhas failed to receive the corresponding packets. If the transmitterreceives the NACK signal, the transmitter retransmits the correspondingpackets to the receiver.

In addition to the general ARQ scheme in which reception results areacknowledged on a packet-by-packet basis, there is a block ARQ scheme inwhich reception results of a plurality of transmitted packets areacknowledged as a group through a block ARQ message.

FIG. 1 is a diagram illustrating a basic concept of a general block ARQscheme based on an example which presumes that the block ARQ scheme isapplied to every three packets.

Referring to FIG. 1, a transmitter transmits three packets, that is,Packet #1, Packet #2 and Packet #3, in sequence. The three packets(Packet #1 to Packet #3) have the same Destination Address (DA), forexample, DA2. Each of the packets (Packet #1 to Packet #3) is providedwith a Sequence Number (SN) and a Fragmentation Number (FN). The SNsignifies the order in which packets are transmitted from an upperlayer. Even packets having the same SN may be transmitted over aplurality of packets as occasion demands. The FN signifies the order oftransmitting the plurality of packets divided over the transmission frompacket having the one same SN.

A receiver checks whether or not packets are continuously received andwhich packets are not received by comparing the SN and the FN of areceived packet with those of previously received packets. In thefollowing description, packets at an SN level will be referred to as ‘SNlevel packets’, and packets divided from the SN level packets will bereferred to as ‘fragmentation packets’. When a packet is not referred toas the SN level packet or the fragmentation packet, but simply referredto as ‘a packet’, it is meant to incorporate both of the above-mentionedtwo types of packets.

Of the three packets, the first and second packets (Packet #1, Packet#2) are fragmentation packets having the same SN (e.g., SN 1) anddifferent FNs (e.g., Frag 1, Frag 2). The third packet (packet #3) is anSN level packet having a different SN (e.g., SN 2) from that of thefirst and second packets (Packet #1, Packet #2).

In FIG. 1, it is assumed that the receiver succeeds in receiving thefirst and third packets (Packet #1, Packet #3) and fails to receive thesecond packet (Packet #2).

The receiver configures a block ACK message on the basis of thereception result as stated above and transmits the configured block ACKmessage to the transmitter. The block ACK message includes a header anda payload. A Destination Address DA1 is recorded in the header. TheDestination Address DA1 is an address of the transmitter. The receptionresults for the respective received packets are recorded in the payload.

Applying the above-mentioned assumption, the ACK information is recordedas the reception result corresponding to the first and third packets(Packet #1, Packet #3), and NACK information is recorded as thereception result corresponding to the second packet (Packet #2). SNs andFNs of the corresponding packets are recorded together in the receptionresults.

The transmitter receives the block ACK message. The transmitter confirmsthrough the block ACK message that the receiver succeeds in receivingthe first and third packets (Packet #1, Packet #3) and failed to receivethe second packet (Packet #2). Thereafter, although not shown in FIG. 1,the transmitter retransmits the second packet (Packet #2).

The above-mentioned scheme in which the reception results for all thereceived packets are recorded in one block ACK message can be realizedin various ways. However, in order to use a message having the shortestlength, a bitmap scheme is employed.

FIGS. 2 to 4 show examples of using the bitmap scheme for acknowledgingreception results.

Referring to FIG. 2, the block ACK message includes a block ACK startingsequence field and a bitmap field. The bitmap field consists of N ACKreport fields. ‘N’ is a value corresponding the maximum SN and signifiesthe maximum number of sequences capable of being acknowledged. That is,‘N’ may be defined as the maximum allowable number of SN level packetswhich can be processed by one block ACK message.

The first SN level packet, with which a bitmap in a correspondingmessage deals, is recorded in the block ACK starting sequence field.Each of reception results for N consecutive packets starting from thepacket having the SN recorded in the block ACK starting sequence fieldis recorded in the bitmap Field.

The respective ACK report fields constituting the bitmap field aredivided into (M×8) regions b0, b1, b2, . . . , b(n), . . . , b(8×M−1)corresponding to the number of fragmentation packets which can bedivided to the maximum extent from one SN level packet. Hereinafter,such regions b0, b1, b2, . . . , b(n), . . . , b(8×M−1) will be referredto as ‘reception result information fields’. This is because receptionresults are acknowledged on a packet-by-packet basis. Thus, if thereception result is expressed by one bit, M octets are required for thetotal reception results information fields for one SN level packet, andso the bitmap field has an overall length of M×N octets.

For example, when SN=1 is recorded in the block ACK starting sequencefield, the reception result for a fragmentation packet having SN=1 andFN=n−1 will be recorded in the reception result information field b(n)210. If the receiver succeeds in receiving this fragmentation packet,‘1’ is recorded in the reception result information field b(n) 210.Otherwise, if the receiver fails in receiving the fragmentation packet,‘0’ is recorded in the reception result information field b(n) 210. Thisis based on the assumption that ‘1’ is an indicator bit representingreception success and ‘0’ is an indicator bit representing receptionfailure. As another example, when ‘5’ is recorded in the block ACKstarting sequence field, ‘1’ is set to a third bit of the second octetif a fragmentation packet having SN=6 and FN=3.

FIG. 3 shows the above-mentioned general example when applied to asystem based on the IEEE 802.16 standard (the 802.16), and FIG. 2 showsthe same example when applied to a system based on the IEEE 802.11estandard (the 802.11e).

A block ACK message shown in FIG. 3 includes a connection ID field, anACK control field and a plurality of ACK MAP fields. The ACK controlfield includes a field in which a starting SN is recorded, and a fieldin which the number of ACK MAPs (m) is recorded. The ACK MAP fields areequal in number to the number of ACK MAPs (m). The ACK MAP field has thesame structure as that of the ACK report field in FIG. 2. In FIG. 3,each of the connection ID field, the ACK control field and the pluralityof ACK MAP fields are configured as a 2-octet field. Thus, the block ACKmessage has an overall length of ‘(m+2)×2’. Usually, ‘m’ is a variablevalue and the maximum number of fragmentation packets is 16 in the802.16.

A block ACK message shown in FIG. 4 includes a BA starting sequencecontrol field and a BA bitmap field. Information indicating a startingsequence recorded in the bitmap field is recorded in the BA startingsequence control field. The BA bitmap field consists of a plurality ofACK MAP fields. Each ACK MAP field has the same structure as that of theACK report field in FIG. 2. For example, in the 802.11e, it is possibleto simultaneously perform ACK processing for a maximum of 64 SN levelpackets, and one SN level packet can be divided into 16 fragmentationpackets. Thus, when each ACK MAP field is configured as a 2-octet field,the BA bitmap field must maintain a size of 128 octets.

SUMMARY

As stated above, if reception results are acknowledged using theconventional bitmap scheme, a wasting of resources occurs. That is, inconventional bitmap scheme, the bitmap is configured by taking intoconsideration that the respective SN level packets will be divided intomaximum fragmentation packets. Thus, when a reception resultcorresponding to an SN level packet, which is not divided intofragmentation packets or is not divided into a maximum number offragmentation packets, is transmitted, reception result informationfields not used in the bitmap field occur. Such reception resultinformation fields may be said to be unnecessary resources.

Accordingly, the present invention has been made to solve at least theabove-mentioned problems occurring in the prior art, and an object ofthe present invention is to provide a method for minimizing the lengthof a message to be transmitted.

It is a further object of the present invention to provide a method forassigning indicator bit regions to a reception result transmittingmessage, which enables an unsuccessfully received packet to be quicklyconfirmed.

It is a further object of the present invention to provide a method fortransmitting only reception result information for unsuccessfullyreceived packets.

It is a further object of the present invention to provide a method forconfirming unsuccessfully received packets through indicator bitscorresponding to the respective packets and transmitting only receptionresult information for the unsuccessfully received packets.

It is a further object of the present invention to provide a method fordetermining the size of a bitmap field, in which reception resultinformation is recorded, in a message transmitting the reception resultinformation based on the number of unsuccessfully received packets.

It is a further object of the present invention to provide a method forexpanding message regions for transmitting reception result informationwhen the number of unsuccessfully received packets exceeds a thresholdvalue.

It is a further object of the present invention to provide a method foroptimizing the size of a bitmap by prior negotiation.

It is a further object of the present invention to provide a framestructure for optimizing the size of a bitmap by prior negotiation.

It is a further object of the present invention to provide a method fortransmitting the number of SN level packets and the number offragmentation packets from a transmitting party to a receiving party inorder to optimize the size of a bitmap.

It is a further object of the present invention to provide a method foroptimizing the size of a bitmap by the number of SN level packets andthe number of fragmentation packets.

It is a further object of the present invention to provide a framestructure for optimizing the size of a bitmap by the number of SN levelpackets and the number of fragmentation packets.

In order to accomplish these objects, in accordance with a first aspectof the present invention, there is provided a method for configuring areception result reporting message for reporting to a transmitterreception results for received packets in a receiver of a mobilecommunication system in which a plurality of packets to be consecutivelytransmitted are transmitted as a plurality of fragmentation packets, themethod includes recording indicators, each of which indicates receptionsuccess or failure for each of the received packets, in a first bitmapfield of the reception result reporting message; and creating a secondbitmap field, in which reception results corresponding to theunsuccessfully received packets of the received packets will berecorded, in the reception result reporting message, and recordingindicator bits, each of which indicates reception success or failure foreach of the fragmentation packets of the unsuccessfully receivedpackets, in the second bitmap field.

In order to accomplish the above-mentioned objects, in accordance with asecond aspect of the present invention, there is provided a method forretransmitting packets in response to a reception result reportingmessage from a receiver in a transmitter of a mobile communicationsystem in which a plurality of packets to be consecutively transmittedare transmitted as a plurality of fragmentation packets, the methodincludes checking if unsuccessfully received packets exist throughindicators of the respective plural packets, which are recorded in afirst bitmap field of the reception result reporting message;identifying unsuccessfully received fragmentation packets correspondingto the unsuccessfully received packets through indicator bits whichexist in a second bitmap field of the reception result reportingmessage; and retransmitting the unsuccessfully received fragmentationpackets or the packets including the unsuccessfully receivedfragmentation packets.

In order to accomplish the above-mentioned objects, in accordance with athird aspect of the present invention, there is provided a method forconfiguring bitmaps in a mobile communication system, the methodincludes receiving information about the number of consecutivelyreceived packets and the maximum number of fragmentation packets; anddetermining a bitmap configuration scheme by the information about thenumber of consecutively received packets and the maximum number offragmentation packets.

In order to accomplish the above-mentioned objects, in accordance with afourth aspect of the present invention, there is provided a method forrequesting reception results for transmitted packets in a mobilecommunication system, the method includes consecutively transmitting apredetermined number of packets (m) while the respective packets aredivided into one or more fragmentation packets; and transmittinginformation about the number of consecutively transmitted packets (m)and the number of fragmentation packets (n).

In order to accomplish the above-mentioned objects, in accordance with afifth aspect of the present invention, there is provided a method forreporting reception results for received packets in a mobilecommunication system, the method includes consecutively receiving mpackets divided into one or more fragmentation packets; receivinginformation about the number of consecutively received packets (m) andthe number of fragmentation packets (n); determining a bitmapconfiguration scheme by the information about the number ofconsecutively received packets (m) and the number of fragmentationpackets (n); configuring the bitmaps including reception results for therespective fragmentation packets by the determined bitmap configurationscheme; and transmitting the bitmaps.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram illustrating a basic concept of a general block ARQscheme;

FIGS. 2 to 4 are diagrams showing examples of acknowledging receptionresults using various conventional bitmap schemes;

FIG. 5 is a diagram showing a hierarchical bitmap structure proposedaccording to the present invention;

FIGS. 6 and 7 are diagrams showing examples of acknowledging receptionresults when the present invention is applied t to the 802.11n;

FIG. 8 is a control flowchart for explaining operations at atransmitting party in accordance with a preferred embodiment of the ofthe present invention;

FIG. 9 is a control flowchart for explaining operations at a receivingparty in accordance with a preferred embodiment of the of the presentinvention;

FIG. 10 is a diagram showing a structure of a block ACK request frame inaccordance with a preferred embodiment of the present invention;

FIG. 11 is a diagram showing a structure of a block ACK frame inaccordance with a preferred embodiment of the present invention; and

FIGS. 12A to 12C, 13A to 13C, and 14A to 14C are diagrams showingoperational examples in accordance with preferred embodiments of thepresent invention.

DETAILED DESCRIPTION

Hereinafter, preferred embodiments of the present invention will bedescribed with reference to the accompanying drawings. It should benoted that the similar components are designated by similar referencenumerals although they are illustrated in different drawings. Also, inthe following description, a detailed description of known functions andconfigurations incorporated herein will be omitted when it may obscurethe subject matter of the present invention.

The present invention proposes a message which has a structure enablingthe size of a field (bitmap field) containing information according toreception results to be optimized while fully performing its intrinsicfunction of acknowledging the reception results. Also, the presentinvention proposes a message which has a structure significantlyreducing the size of the bitmap . In the following description, a bitmapconfiguring method in which the size of the bitmap is reduced byreporting only reception results for unsuccessfully received packetswill be proposed as a first preferred embodiment. In addition, a bitmapconfiguring method in which the size of the bitmap is optimized byreporting reception results based on information provided by atransmitting party will be proposed as a second preferred embodiment.

Hereinafter, the first preferred embodiment of the present inventionwill be describe in detail with reference to the accompanying drawings

The first embodiment of the present invention may be realized based ontwo considerations.

First, a Packet Error Rate (PER) in a general wireless datacommunication system is designed at a lower level. Second, packet lossesare concentrated at a specific moment rather than uniformly distributed.

In view of the two considerations, the number of erroneous packets maybe very small and errors may concentrically occur at a specific moment,if any. Thus, it may be expected to succeed in receiving most packetsand fail in receiving only some packets even if reception failuresoccur.

If an ARQ scheme is realized such that only reception results forunsuccessfully received packets are acknowledged, the amount ofinformation according to the acknowledgment of the reception results canbe greatly reduced. The reduction in the amount of information accordingto the acknowledgment of the reception results means that the size ofthe bitmap is reduced.

In the following detailed description, there is proposed a block ACKmessage for reporting only reception results corresponding tounsuccessfully received fragmentation packets of fragmentation packetstransmitted from an SN level packet. To this end, a field (herein afterreferred to as ‘SN level bitmap field’) for transmitting indicatorswhich enables success or failure in receiving each of the maximumallowable SN level packets treatable by the block ACK to be confirmed isnewly defined. Also, a field (hereinafter referred to as ‘ACK reportfield’) for transmitting concrete reception results corresponding to theunsuccessfully received SN level packet is newly defined. Here, theconcrete reception results are indicators which enable success orfailure in receiving each of the fragmentation packets transmitted fromone SN level packet to be confirmed.

In order to configure such a block ACK message, a transmitting party (aparty having received packets) checks on an SN-by-SN basis ifunsuccessfully received packets exist. Subsequently, for theunsuccessfully received packets, a transmitting party sets ‘receptionfailure’ to indicators corresponding to the SNs of the unsuccessfullyreceived packets in the SN level bitmap field. In contrast with this,for successfully received packets, a transmitting party sets ‘receptionsuccess’ to indicators corresponding to the SNs of the successfullyreceived packets in the SN level bitmap field.

However, when a plurality of fragmentation packets having the same SNare received, it is not possible to confirm reception results for thefragmentation packets by only the SN level bitmap field. In this case,separate information enabling unsuccessfully received fragmentationpackets to be confirmed is required.

In the first embodiment of the present invention, therefore, the ACKreport fields are separately created according to the SNs of theunsuccessfully received packets. Indicators corresponding to therespective fragmentation packets are recorded, that is, indicators arerecorded on an FN-by-FN basis in the ACK report fields. These indicatorsrepresents reception success or reception failure for the fragmentationpackets having the same SN. The ACK report fields are configured bytaking into consideration the maximum number of fragmentation packetsfrom one SN level packet.

The transmitting party transmits the so-configured block ACK message toa receiving party.

The receiving party (a party having transmitted packets) confirmsreception success or failure for the respective SN level packets bychecking the indicators recorded in the SN level bitmap field of theblock ACK message. When unsuccessfully received SN level packets exist,the receiving party checks the ACK report fields corresponding to theunsuccessfully received SN level packets. The receiving party isnotified of the unsuccessfully received fragmentation packets throughthe indicators recorded in the ACK report fields.

FIG. 5 shows a hierarchical bitmap structure proposed according to thepresent invention.

Referring to FIG. 5, a block ACK message having the hierarchical bitmapstructure includes a block ACK starting sequence field and a bitmapfield. The bitmap field consist of an SN level bitmap field and anerroneous SN packet bitmap field. The erroneous SN packet bitmap fieldincludes a plurality of ACK report fields (M×m ACK fields). Here, ‘m’corresponds to the number of zeros (‘0’) set to the SN level bitmapfield. ‘M’ is the number of unsuccessfully received SN level packets.

The SN of the first SN level packet with which bitmaps in acorresponding message deal is recorded in the block ACK startingsequence field. At this time, the first SN level packet may be definedas the first SN level packet to be acknowledged through the block ACKmessage. Here, it should be noted that the first SN level packet mustnot be interpreted as the first unsuccessfully received SN level packet.

Indicators (hereinafter referred to as ‘SN quick reference bits’)representing the reception results (reception success or failure)according to the respective SNs are recorded in the SN level bitmapfield. The length of the SN level bitmap field is determined by thenumber of maximum allowable SN level packets that can be processed bythe block ACK. That is, if the number of maximum allowable SN levelpackets that can be processed by the block ACK is 8×N, the SN levelbitmap field has a length of N octets (8×N bits). Thus, each bitconstituting the SN level bitmap field is used as the SN quick referencebit assigned SN by SN.

The erroneous SN packet bitmap field includes ACK report fields. Sincethe ACK report fields are separately created according to the SNs of theunsuccessfully received packets, the number of ACK report fields must beequal to the number of the unsuccessfully received SN level packets.Thus, the erroneous SN packet bitmap field has a length of M×m octets.Here, M octets, the overall length of the ACK report fields, is a fixedvalue, so the overall length of the erroneous SN packet bitmap field(M×m octets) is determined by the number of the unsuccessfully receivedSN level packets (m).

For example, the greater the number of the unsuccessfully received SNlevel packets (m), the longer the overall length of the erroneous SNpacket bitmap field (M×m octets). In contrast with this, the lesser thenumber of unsuccessfully received SN level packets (m), the shorter theoverall length of the erroneous SN packet bitmap field (M×m octets). Ifthere are no unsuccessfully received SN level packets, the erroneous SNlevel packet bitmap field may not exist.

A mapping relation between the ACK report fields and the SN quickreference bits set as ‘0’ can be established in various ways. In thesimplest example, the ACK report fields are sequentially mappedcorresponding to the SN order of the SN quick reference bits.

For example, if it is assumed that a value of the block ACK startingsequence field is 5 and a value of the SN level bitmap field is11101011, two ACK report fields exist in the erroneous SN packet bitmapfield. A first of the two ACK report fields becomes a bitmap of an SNlevel packet having SN=8, and a second becomes a bitmap of an SN levelpacket having SN=10. Also, a scheme in which indicators are assigned tothe ACK report fields may be employed.

Indicators for reporting reception results for the respectivefragmentation packet are recorded in the ACK report fields. Thus, theindicators exist corresponding to the maximum number of fragmentationpackets that one SN level packet (M×8) can be divided into. This isbecause the reception results are acknowledged on a fragmentationpacket-by-fragmentation packet basis. In FIG. 5, the indicators aredesignated by ‘b0, b1, b2, . . . , b(n), . . . , b(8×M−1)’. For example,if the indicator is expressed by one bit, one ACK report field has alength of M octets.

Hereinafter, a description will be given for an example of actuallyconfiguring the block ACK message having the structure as shown in FIG.5.

When all fragmentation packets divided from an SN level packet havingSN=n+1 are successfully received, an (n+1)−th SN quick reference bitb(n) in the SN level bitmap field is set as ‘1’. However, when even onefragmentation packet is unsuccessfully received, the an (n+1)−th SNquick reference bit b(n) in the SN level bitmap field is set as ‘0’.That is, when even one fragmentation packet is unsuccessfully received,a quick reference bit corresponding to the SN of the unsuccessfullyreceived fragmentation packet is set as “reception failure’. In thiscase, there must be provided separate information which enables theunsuccessfully received fragmentation packets to be confirmed.

If it is assumed that a fragmentation packet having SN=n+1 and FN n+1 isunsuccessfully received, an (n+1)−th SN quick reference bit, that is,b(n) in the SN level bitmap field, is set as ‘0’, and an ACK reportfield (hereinafter referred to as ‘m-th ACK report field’) to be mappedto b(n) is assigned to the SN packet bitmap field. Subsequently, a bitrepresenting reception failure is set to an (n+1)−th indicator b(n) inthe m-th ACK report field. At this time, a bit representing receptionsuccess is set to the remaining indicators except the (n+1)−th indicatorb(n) in the m-th ACK report field. As an example, ‘0’ is used as theindicator representing reception failure and ‘1’ is used as theindicator representing reception success.

FIGS. 6 and 7 show examples of a message for reporting reception resultswhen the present invention as described above is applied to a systembased on the IEEE 802.11n standard (the 802.11n). The examples shown inFIGS. 6 and 7 are distinguished from each other by the number ofunsuccessfully received packets. That is, if the number ofunsuccessfully received MAC service data unit (MSDUs) does not reach athreshold value (e.g., 12), a message structure shown in FIG. 6 isemployed. However, if the number of unsuccessfully received MSDUs isequal to or greater than the threshold value (e.g., 12), a messagestructure shown in FIG. 7 is employed.

Referring to FIG. 6, the block ACK message includes a BA control field,a BA starting sequence control field and a BA erroneous MSDUs' bitmapfield.

The BA control field has a length of 2 octets. The BA control fieldincludes a BA MSDUs' bitmap field and a TID field. The BA MSDUs' bitmapfield consists of quick reference bits for representing receptionsuccess or failure for the respective SN level packets. The BA MSDUs'bitmap field is a region which has not been used in the existing 802.11and is reused for the present invention. Since FIG. 6 supposes a casewhere the number of unsuccessfully received MSDUs is below 12, the BAMSDUs' bitmap field is configured with a size of 12 bits.

In addition, any one bit in the BA control field can be assigned for amessage indicator. As an example, the first one bit of the BA controlfield may be assigned for the message indicator. The message indicatorindicates a message type. In FIG. 6, ‘1’ is used as the messageindicator.

The SN of the first SN level packet with which bitmaps in acorresponding message deal is recorded in the BA starting sequencecontrol field. The first SN level packet is a packet which istransmitted first from among consecutively transmitted packets for theblock ACK, and it should be noted that the first SN level packet is notthe first unsuccessfully received SN level packet.

The BS erroneous MSDUs' bitmap field consists of a plurality of ACK MAPfields not exceeding 11 in number. The BA erroneous MSDUs' bitmap fieldhas the same structure and function as those of the erroneous SN packetbitmap field described above with reference to FIG. 5, thus, a detaileddescription of the BA erroneous MSDUs' bitmap field will be omitted.

Referring to FIG. 7, the block ACK message includes a BA control field,a BA starting sequence control field, a BA MSDUs' bitmap field and a BAerroneous MSDUs' bitmap field.

Any one bit in the BA control field is assigned for a message indicator.As an example, the first one bit of the BA control field may be assignedfor the message indicator. In FIG. 7, ‘0’ is used as the messageindicator. In addition, another one bit in the BA control field isassigned for a success indicator. The success indicator indicates thatall packets (64 MSDUs' are assumed in FIG. 7) are successfully received(designated by ‘A’ in the drawing). When all SN level packets aresuccessfully received, the success indicator is set as ‘1’. However,when even one SN level packet is unsuccessfully received, the successindicator is set as ‘0’. If the success indicator is set as ‘1’, the BSMSDUs' bitmap field and the BA erroneous packet bitmap field are notneeded.

The BA MSDUs' bitmap field carries out the same function as that of theBA MSDUs' bitmap field existing in the BA control field as shown in FIG.6, so a detailed description thereof will be omitted. The onlydifference between both the BA MSDUs' bitmap fields is that the BAMSDUs' bitmap field in FIG. 7 has a size of 64 bits (8 octets) so as torepresent reception success or failure for 64 packets.

The BA erroneous MSDUs' bitmap field consists of ACK MAP fieldscorresponding to the number of unsuccessfully received packets. The BAerroneous MSDUs' bitmap field has the same structure and function asthose of the erroneous SN packet bitmap field described above withreference to FIG. 5, thus, a detailed description of the BA erroneousMSDUs' bitmap field will also be omitted.

Hereinafter, a second preferred embodiment of the present invention willbe describe in detail with reference to the accompanying drawings.

The second embodiment of the present invention premises a system fortransmitting a block ACK request frame together with consecutive dataframes from a transmitting party to a receiving party. The block ACKrequest frame includes information needed for transmitting the receptionresults of the respective data frames. The block ACK request frame maybe transmitted before or after the transmission of the data frames. Ofcourse, it is possible to simultaneously transmit the block ACK requestframe and the data frames.

The receiving party receives the data frames and the block ACK requestframe. The receiving party determines a bitmap configuration scheme onthe basis of the information received through the block ACK requestframe, and then configures the bitmaps according to the determinedbitmap configuration scheme such that the bitmaps include receptionresults for the data frames. The bitmaps are acknowledged to thetransmitting party through a bloc ACK frame.

In the second embodiment of the present invention, information about‘the number of SN level packets to be consecutively transmitted (m)’ and‘the maximum number of fragmentation packets (n)’ are transmittedthrough the block ACK request frame. Usually, the SN level packet istransmitted having been divided into a plurality of fragmentationpackets, if necessary. The maximum number of fragmentation packets (n)is the maximum number of fragmentation packets that can be made from theSN level packets to be transmitted.

In the following description, an operation for transmitting the blockACK request frame at the transmitting party and a structure of the blockACK request frame will be discussed in detail. Also, an operation forreporting reception results on a fragmentation packet-by-fragmentationpacket basis through the block ACK frame at the receiving party and astructure of the block ACK frame will be discussed in detail.

Furthermore, in an example of the present invention, there will bediscussed an operation performed when the number of packets to beconsecutively transmitted (m) and the maximum number of fragmentationpackets are randomly given.

Hereinafter, the operations of the transmitting and receiving parties inaccordance with preferred embodiments of the present invention will bedescribed in detail.

FIG. 8 shows a control flow for explaining the operation of thetransmitting party in accordance with a preferred embodiment of thepresent invention.

Referring to FIG. 8, in step 810, the number of packets to betransmitted (m) is determined. The determination of ‘m’ is effected bythe number of SN level packets to be consecutively transmitted. Each SNlevel packet may be transmitted dividedly into plural fragmentationpackets. In step 812, the maximum number of fragmentation packets isdetermined, or in other words the division status of each SN levelpacket is confirmed. That is, the numbers of fragmentation packetsdivided from the respective SN level packets are detected and the SNlevel packet, from which the most fragmentation packets are divided, isdetermined . The number of fragmentation packets divided from the foundSN level packet is determined as the maximum number of fragmentationpackets (n).

In step 814, the Block ACK Request (BAR) frame is configured such that‘m’ and ‘n’ as determined above are included in the BAR frame. At thistime, the SN of the first SN level packet to be transmitted is recordedin the block ACK starting sequence control field of the BAR frame. Thetransmitting party transmits the BAR frame to the receiving party. Astructure of the BAR frame will be discussed with respect to FIG. 10.

Although not shown in FIG. 8, m SN level packets may be transmittedbefore or after the transmission of the corresponding BAR frame. Ofcourse, it is possible to simultaneously transmit the SN level packetswith the BAR frame. Also, the receiving party provides to thetransmitting party the reception results corresponding to the respectivefragmentation packets of m SN level packets. The reception results, on afragmentation packet-by fragmentation packet basis, are provided throughthe Block ACK (BA) frame. The transmitting party retransmits thefragmentation packets based on the reception results for the respectivefragmentation packets acquired through the BA frame.

FIG. 9 shows a control flow for explaining the operation of thereceiving party in accordance with a preferred embodiment of the presentinvention.

Referring to FIG. 9, in step 910, the receiving party receives the BARframe. In step 912, the receiving party confirms ‘m’ and ‘n’ from theBAR frame.

Once the receiving party confirms ‘m’ and ‘n’, it determines a bitmapconfiguration scheme through steps 914 to 918. The bitmap configurationscheme is determined by the overall bitmap size, the bitmap sizecorresponding to one SN level packet and the number of bits to bepadding-processed.

In step 914, the overall bitmap size is determined. The overall bitmapsize is determined by ‘m’ and ‘n’ previously confirmed in step 912. Asan example, the overall bitmap size can be determined by Equation (1) asfollows:

Overall bitmap size=ceiling[m×n/8] octets . . .   (1)

where ceiling [x] denotes a minimum integer from among integersexceeding ‘x’. The overall bitmap size may also be expressed as theoverall bitmap size in bit by multiplying the overall bitmap size inoctet by ‘8’.

For example, if ‘m’ is 2 and ‘n’ is 7, the overall bitmap size isexpressed by ‘ceiling [1.75]’. Since ‘ceiling [1.75]’ denotes a minimuminteger from among integers larger than ‘1.75’, it results in ‘2’. Thus,the overall bitmap size is determined as 2 octets.

In step 916, the bitmap sizes to be assigned to the respective SN levelpackets are determined. Preferably, the same bitmap size is assigned toall the SN level packets. When the same bitmap size is assigned in thisway, the bitmap size for only one SN level packet is determined and thedetermined bitmap size can be applied to the remaining SN level packets.For example, the bitmap size is determined as ‘n’ previously confirmedin step 912. This is because reception results must be acknowledged on afragmentation packet-by-fragmentation packet basis.

According to the above-mentioned description, the sum of the bitmapsizes to be assigned to the respective SN level packets dos not exceedthe overall bitmap size. That is, when the bitmap sizes are assigned tothe respective SN level packets, the sum of the bitmap sizes is equal tothe overall bitmap size or the remaining bits occur. In step 918, thenumber of bits to be padding-processed is determined. However, when thesum of the bitmap sizes assigned to the respective SN level packets isequal to the overall bitmap size, there is no remaining bit, and nopadding is required. The number of bits to be padded can be generalizedby Equation (2) as follows:

ceiling [m×n/8]×8×m×n  (2)

The unit of Equation (2) is a bit. The bitmap configuration scheme isdetermined by the overall bitmap size, the bitmap sizes according to therespective SN level packets and the number of bits to bepadding-processed previously determined through steps 914 to 918. Also,bit values according to the reception results on a fragmentationpacket-by-fragmentation packet basis are inserted in corresponding bitpositions. As for the bit positions, refer to SNs and FNs which thefragmentation packets have ‘1 (success)’ and ‘0 (failure)’ are used asthe bit values according to the reception results.

The bitmap structure will be described with reference to FIG. 11.Examples of inserting the bit values according to the reception resultsfor the respective fragmentation packets in the corresponding bitpositions are illustrated in FIGS. 12 to 14. These examples will also bedescribed later in detail.

In step 922, the BA frame including the bitmaps is configured andtransmitted to the transmitting party.

Hereinafter, a structure of the BAR frame transmitted from thetransmitting party in accordance with the second embodiment of thepresent invention will be described in detail.

The structure of the BAR frame proposed in the second embodiment of thepresent invention is characterized in that it includes information aboutthe number of SN level packets to be consecutively transmitted (m) andthe number of fragmentation packets of the SN level packet divided themost (n).

FIG. 10 illustrates a structure of the BAR frame, on which theabove-mentioned characteristic is reflected.

Referring to FIG. 10, the BAR frame includes a BAR control field and aBA starting sequence control field. The sizes of the BAR control fieldand the BA starting sequence control field are 2 octets each.

The BAR control field includes a ‘Num of MSDUs’ field and a ‘Max. num ofFrag’ field. The number of SN level packets to be consecutivelytransmitted (m) is recorded in the ‘Num of MSDUs’ field. The number offragmentation packets of the SN level packet divided the most (n) isrecorded in the ‘Max. num of Frag’ field. The size of the ‘Num of MSDUs’field is 6 bits, and the size of the ‘Max. num of Frag.’ Field is 4bits.

The SN of the first SN level packet to be transmitted from among theconsecutively transmitted SN level packets is recorded in the BAstarting sequence control field.

Hereinafter, a structure of the BA frame transmitted to the receivingparty in accordance with the second embodiment of the present inventionwill be described in detail.

The structure of the BA frame proposed in the second embodiment of thepresent invention is characterized in that it has a bitmap structurewhich is optimized using ‘m’ and ‘n’ provided from the transmittingparty.

FIG. 11 illustrates a structure of the BA frame, on which theabove-mentioned characteristic is reflected.

Referring to FIG. 11, the BA frame includes a BA starting sequencecontrol field and a BA bitmap field.

The most preceding SN level packet from among the consecutively receivedSN level packets is recorded in the BA starting sequence control field.

The overall size of the BA bitmap field is determined by Equation (1).That is, the overall size of the BA bitmap field can be determined by‘m’ and ‘n’ received through the BAR frame. The BA bitmap field consistsof m bitmaps. Each of m bitmaps is configured with a size of n bits.Each bit constituting the bitmaps represents a reception result of acorresponding fragmentation packet. Each of the bitmaps corresponds toone of the consecutively received SN level packets, and a receptionresult for the corresponding SN level packet is recorded in the bitmap.At this time, a bit position, in which the reception result for thefragmentation packet is recorded within the bitmap, is assigned by theSN and the FN of the fragmentation packet. The remaining bits, which arenot used as the bitmaps in the BA bitmap field, are subjected to thepadding processing. The number of bits to be padded can be derived byEquation (2).

Hereinafter, case-by-case operations in accordance with the secondembodiment of the present invention will be described.

FIGS. 12A to 12C are views for explaining an operational example in acase where all SN level packets consecutively transmitted from thetransmitting party are successfully received.

FIG. 12A shows that three SN level packets (SN=10, 11, 12) areconsecutively transmitted. Here, the SN level packet having SN=10 aredivided into four fragmentation packets 10-1, 10-2, 10-3, 10-4, the SNlevel packet having SN=11 are divided into three fragmentation packets11-1, 11-2, 11-3, and the SN level packet having SN=12 are divided intofive fragmentation packets 12-1, 12-2, 12-3, 12-4, 12-5. Thus, ‘m’ isdetermined as ‘3’, and ‘n’ is determined as ‘5’. The reason why ‘n’ isdetermined as ‘5’ is that the number of fragmentation packets dividedthe most from one SN level packet is ‘5’.

FIG. 12B shows a BAR frame structure in which m=‘3’ and n=‘5’ are set inthe BAR control field. The SN of a SN level packet which is transmittedfirst from among the three consecutively transmitted SN level packets is‘10’. Thus, ‘10’ is recorded in the BA starting sequence control field.

If the receiving party receives the BAR frame having the structure asshown in FIG. 12B, it confirms information recorded in the BAR controlfield and the BA starting sequence control field. Hereby, the receivingparty recognizes that the three SN level packets having SNs of 10, 11and 12 are consecutively transmitted and the number of fragmentationpackets divided the most is ‘5’.

Subsequently, the receiving party determines the overall bitmap size byEquation (1). According to Equation (1), the overall bitmap size isdetermined as 2 octets (16 bits). Indicator bits indicating receptionresults corresponding to the respective SN level packets are determinedas a 5-bit indicator bit. This is because the SN level packet havingSN=12 is divided into five fragmentation packets and at least 5 bits arerequired for indicating reception results on a fragmentationpacket-by-fragmentation packet basis.

The four fragmentation packets constituting the SN level packet havingSN=10 have been all successfully received. Thus, the indicator bitindicating the reception result for the SN level packet having SN=10 isset as ‘11110’ (designated by {circle around (1)} in FIG. 12C). Theupper four bits set as ‘1’ indicate that the respective fragmentationpackets have been successfully received. The last bit is set as ‘0’because there is no fragmentation packet corresponding to that bit.

The three fragmentation packets constituting the SN level packet havingSN=11 have been all successfully received. Thus, the indicator bitindicating the reception result for the SN level packet having SN=11 isset as ‘11100’ (designated by {circle around (2)} in FIG. 12C). Theupper three bits set as ‘1’ indicate that the respective fragmentationpackets have been successfully received. The lower 2 bits are set as ‘0’because there is no fragmentation packet corresponding to those bits.

The five fragmentation packets constituting the SN level packet havingSN=12 have been all successfully received. Thus, the indicator bitindicating the reception result for the SN level packet having SN=12 isset as ‘11111’ (designated by {circle around (3)} in FIG. 12C). The fivebits set as ‘1’ indicate that the respective fragmentation packets havebeen successfully received.

Once the 5-bit indicator bits indicating the reception results for therespective SN level packets are assigned, the remaining bit of 1 bitoccurs in the bitmap the overall size of which has been determined as 2octets (16 bits). This is determined by Equation (2). The receivingparty performs padding for the remaining bit. That is, the remaining bitis set as ‘0’.

In conclusion, the reception result for the three consecutivelytransmitted SN level packets is determined as ‘11110 11100 11111 0’. Thedetermined reception result is recorded in the BA bitmap field of the BAframe. Also, ‘10’ is recorded in the BA starting sequence control fieldof the BA frame.

FIGS. 13A to 13C and FIGS. 14A to 14C are views for explainingoperational examples in a case where some SN level packets areunsuccessfully received from among SN level packets consecutivelytransmitted from the transmitting party.

FIG. 13A shows that three SN level packets (SN=10, 11, 12) areconsecutively transmitted. Here, the SN level packet having SN=10 aredivided into four fragmentation packets 10-1, 10-2, 10-3, 10-4, the SNlevel packet having SN=11 are divided into three fragmentation packets11-1, 11-2, 11-3, and the SN level packet having SN=12 are divided intofive fragmentation packets 12-1, 12-2, 12-3, 12-4, 12-5. Thus, ‘m’ isdetermined as ‘3’, and ‘n’ is determined as ‘5’. The reason why ‘n’ isdetermined as ‘5’ is that the number of fragmentation packets dividedthe most from one SN level packet is ‘5’. Among the fragmentationpackets, the fragmentation packets corresponding to 11-2, 12-2 and 12-4have been unsuccessfully received.

FIG. 13B shows a BAR frame structure in which m=‘3’ and n=‘5’ are set inthe BAR control field. The SN of a SN level packet to be transmittedfirst is ‘10’. Thus, ‘10’ is recorded in the BA starting sequencecontrol field.

If the receiving party receives the BAR frame having the structure asshown in FIG. 13B, it confirms information recorded in the BAR controlfield and the BA starting sequence control field. Hereby, the receivingparty recognizes that the three SN level packets having SNs of 10, 11and 12 are consecutively transmitted and the number of fragmentationpackets divided the most is ‘5’.

Subsequently, the receiving party determines the overall bitmap size byEquation (1). According to Equation (1), the overall bitmap size isdetermined as 2 octets (16 bits). Indicator bits indicating receptionresults corresponding to the respective SN level packets are determinedas a 5-bit indicator bit. This is because the SN level packet havingSN=12 is divided into five fragmentation packets and at least 5 bits arerequired for indicating reception results on a fragmentationpacket-by-fragmentation packet basis.

The four fragmentation packets 10-1, 10-2, 10-3, 10-4 constituting theSN level packet having SN=10 have been all successfully received. Thus,the indicator bit indicating the reception result for the SN levelpacket having SN=10 is set as ‘11110’ (designated by {circle around (1)}in FIG. 13C). The upper four bits set as ‘1’ indicate that therespective fragmentation packets have been successfully received. Thelast bit is set as ‘0’ because there is no fragmentation packetcorresponding to that bit.

Of the three fragmentation packets 11-1, 11-2, 11-3 constituting the SNlevel packet having SN=11, the fragmentation packets corresponding to11-1 and 11-3 have been successfully received, but the fragmentationpacket corresponding to 11-2 has been unsuccessfully received. Thus, theindicator bit indicating the reception result for the SN level packethaving SN=11 is set as ‘10100’ (designated by {circle around (2)} inFIG. 13C). The bits set as ‘1’ indicate that the correspondingfragmentation packets 11-1, 11-3 have been successfully received. Incontrast with this, the bit set as ‘0’ indicates that the correspondingfragmentation packet 11-2 has been unsuccessfully received. The lower 2bits are set as ‘0’ because there is no fragmentation packetcorresponding to those bits.

Of the five fragmentation packets 12-1, 12-2, 12-3, 12-4, 12-5constituting the SN level packet having SN=12, the fragmentation packetscorresponding to 12-1, 12-3 and 12-5 have been successfully received,but the fragmentation packets corresponding to 12-2 and 12-4 have beenunsuccessfully received. Thus, the indicator bit indicating thereception result for the SN level packet having SN=12 is set as ‘10101’(designated by {circle around (3)} in FIG. 13C). The bits set as ‘1’indicate that the corresponding fragmentation packets 12-1, 12-3, 12-5have been successfully received. In contrast with this, the bits set as‘0’ indicate that the corresponding fragmentation packets 12-2, 12-4have been unsuccessfully received.

Once the 5-bit indicator bits indicating the reception results for therespective SN level packets are assigned, the remaining bit of 1 bitoccurs in the bitmap the overall size of which has been determined as 2octets (16 bits). This is determined by Equation (2). The receivingparty performs padding for the remaining bit. That is, the remaining bitis set as ‘0’.

In conclusion, the reception result for the three consecutivelytransmitted SN level packets is determined as ‘11110 10100 10101 0’. Thedetermined reception result is recorded in the BA bitmap field of the BAframe. Also, ‘10’ is recorded in the BA starting sequence control fieldof the BA frame.

FIG. 14A shows that two SN level packets (SN=10, 11) are consecutivelytransmitted. Here, the SN level packet having SN=10 are divided intoseven fragmentation packets 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7,and the SN level packet having SN=11 are divided into five fragmentationpackets 11-1, 11-2, 11-3, 11-4, 11-5. Thus, ‘m’ is determined as ‘2’,and ‘n’ is determined as ‘7’. The reason why ‘n’ is determined as ‘7’ isthat the number of fragmentation packets divided the most from one SNlevel packet is ‘7’. Among the fragmentation packets, the fragmentationpackets corresponding to 10-3, 10-6 and 11-2 have been unsuccessfullyreceived.

FIG. 14B shows a BAR frame structure in which m=‘2’ and n=‘7’ are set inthe BAR control field. The SN of a SN level packet to be transmittedfirst is ‘10’. Thus, ‘10’ is recorded in the BA starting sequencecontrol field.

If the receiving party receives the BAR frame having the structure asshown in FIG. 14B, it confirms information recorded in the BAR controlfield and the BA starting sequence control field. Hereby, the receivingparty recognizes that the two SN level packets having SNs of 10 and 11are consecutively transmitted and the number of fragmentation packetsdivided the most is ‘7’.

Subsequently, the receiving party determines the overall bitmap size byEquation (1). According to Equation (1), the overall bitmap size isdetermined as 2 octets (16 bits). Indicator bits indicating receptionresults corresponding to the respective SN level packets are determinedas a 7-bit indicator bit. This is because the SN level packet havingSN=10 is divided into seven fragmentation packets and at least 7 bitsare required for indicating reception results on a fragmentationpacket-by-fragmentation packet basis.

Of the seven fragmentation packets 10-1, 10-2, 10-3, 10-4, 10-5, 10-6,10-7 constituting the SN level packet having SN=10, the fragmentationpackets corresponding to 10-1, 10-2, 10-4, 10-5 and 10-7 have beensuccessfully received, but the fragmentation packet corresponding to10-3 and 10-6 have been unsuccessfully received. Thus, the indicator bitindicating the reception result for the SN level packet having SN=10 isset as ‘1101101’ (designated by {circle around (1)} in FIG. 14C). Thebits set as ‘1’ indicate that the corresponding fragmentation packets10-1, 10-2, 10-4, 10-5, 10-7 have been successfully received. Incontrast with this, the bits set as ‘0’ indicate that the correspondingfragmentation packet 10-3, 10-6 have been unsuccessfully received.

Of the five fragmentation packets 11-1, 11-2, 11-3, 11-4, 11-5constituting the SN level packet having SN=11, the fragmentation packetscorresponding to 11-1, 11-3, 11-4 and 11-5 have been successfullyreceived, but the fragmentation packet corresponding to 11-2 has beenunsuccessfully received. Thus, the indicator bit indicating thereception result for the SN level packet having SN=11 is set as‘1011100’ (designated by {circle around (2)} in FIG. 14C). The bits setas ‘1’ indicate that the corresponding fragmentation packets 11-1, 11-3,11-4, 11-5 have been successfully received. In contrast with this, thebit set as ‘0’ indicates that the corresponding fragmentation packet11-2 has been unsuccessfully received. The lower 2 bits are set as ‘0’because there is no fragmentation packet corresponding to those bits.

Once the 7-bit indicator bits indicating the reception results for therespective SN level packets are assigned, the remaining bits of 2 bitsoccur in the bitmap the overall size of which has been determined as 2octets (16 bits). This is determined by Equation (2). The receivingparty performs padding for the remaining bits. That is, the remainingbits are set as ‘0’.

In conclusion, the reception result for the three consecutivelytransmitted SN level packets is determined as ‘1101101 1011100 00’. Thedetermined reception result is recorded in the BA bitmap field of the BAframe. Also, ‘10’ is recorded in the BA starting sequence control fieldof the BA frame.

In the above-mentioned second embodiment of the present invention, it isassumed that the transmitting party provides the number of SN levelpackets to be consecutively transmitted and the maximum number offragmentation packets to the receiving party in order to negotiate thebitmap size in advance. However, the present invention can be realizedin such a manner that the receiving party confirms the number ofconsecutively transmitted SN level packets and the maximum number offragmentation packets by receiving the consecutively transmitted SNlevel packets. In this way, there is no need for transmitting the blockACK request (BAR) frame at the transmitting party.

As described above, the present invention makes it possible toefficiently use transmission resources by providing a hierarchicalbitmap structure. Also, in view of an actual communication environment,it may be expected to not only enhance gains in the transmissionresources, but also have a great effect on performance of a mobilecommunication system. Furthermore, by negotiating the bitmap size inadvance through the block ACK request, the number of bits for reportingreception results can be optimized. This results in effective using ofthe transmission resources and performance improvement of a mobilecommunication system.

While the invention has been shown and described with reference tocertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1. A method for configuring a reception result reporting message forreporting to a transmitter reception results for packets in a receiverof a mobile communication system in which a plurality of packets to beconsecutively transmitted are transmitted by being divided into aplurality of fragmentation packets, the method comprising the steps of:storing indicators, each of which indicates reception success or failurefor each of the packets, in a first bitmap field of the reception resultreporting message; and creating a second bitmap field, in whichreception results corresponding to unsuccessfully received packets ofthe packets will be stored, in the reception result reporting message,and storing indicator bits, each of which indicates reception success orfailure for each of the fragmentation packets of the unsuccessfullyreceived packets, in the second bitmap field.
 2. The method as claimedin claim 1, wherein the number of indicators recorded in the firstbitmap field is determined by the number of consecutively receivedpackets.
 3. The method as claimed in claim 2, wherein if even onefragmentation packet of the fragmentation packets divided from thereceived packets is unsuccessfully received, the indicatorscorresponding to the received packets are set as a value indicatingreception failure.
 4. The method as claimed in claim 1, wherein thenumber of second bitmap fields is determined by the number ofunsuccessfully received packets.
 5. The method as claimed in claim 4,wherein the number of indicator bits recorded in the second bitmap fieldis determined by the maximum number of fragmentation packets dividedfrom one packet.
 6. The method as claimed in claim 3, wherein from amongthe indicator bits in the second bitmap field, the indicator bitscorresponding to the unsuccessfully received fragmentation packets areset as a value indicating reception failure.
 7. The method as claimed inclaim 1, wherein the reception result reporting message is furtherprovided with a field for recording the foremost sequence number (SN) ofthe SNs which are included in the received packets.
 8. A method forretransmitting packets in response to a reception result reportingmessage from a receiver in a transmitter of a mobile communicationsystem in which a plurality of to be consecutively transmitted aretransmitted by being divided into a plurality of fragmentation packets,the method comprising the steps of: determining if unsuccessfullyreceived packets exist by analyzing indicators of the respective pluralpackets, which are recorded in a first bitmap field of the receptionresult reporting message; identifying unsuccessfully receivedfragmentation packets corresponding to the unsuccessfully receivedpackets by analyzing indicator bits which exist in a second bitmap fieldof the reception result reporting message; and retransmitting one of theunsuccessfully received fragmentation packets and the packets includingthe unsuccessfully received fragmentation packets.
 9. The method asclaimed in claim 8, wherein the number of indicators recorded in thefirst bitmap field is equal to the number of the plurality of packets.10. The method as claimed in claim 9, wherein if even one fragmentationpacket of the fragmentation packets divided from the received packetscorresponding to the indicators of the first bitmap field isunsuccessfully received, the indicators are set as a value indicatingreception failure.
 11. The method as claimed in claim 8, wherein thenumber of second bitmap fields is equal to the number of unsuccessfullyreceived packets.
 12. The method as claimed in claim 11, wherein thenumber of indicator bits of the second bitmap field is equal to themaximum number of fragmentation packets divided from one packet.
 13. Themethod as claimed in claim 8, wherein the reception result reportingmessage is further provided with a field for recording therein theforemost SN of the SNs which are included in the plural packets.
 14. Amethod for configuring bitmaps in a mobile communication system, themethod comprising the steps of: receiving information about the numberof consecutively received packets and the maximum number offragmentation packets; and determining a bitmap configuration schemebased on the information about the number of consecutively receivedpackets and the maximum number of fragmentation packets.
 15. The methodas claimed in claim 14, wherein the overall bitmap size for determiningthe bitmap configuration scheme is calculated by the following equation:Overall bitmap size=ceiling[m×n/8]octets where ceiling [x] denotes aminimum integer from among integers exceeding ‘x’, m is the number ofconsecutively received packets, and n is the number of fragmentationpackets.
 16. The method as claimed in claim 15, wherein the bitmap sizecorresponding to each of the consecutively received packets isdetermined as n bits.
 17. The method as claimed in claim 16, wherein outof bits corresponding to the overall bitmap size, the bits correspondingto the number of bits calculated by the following equation arepadding-processed:ceiling[m×n/8]×8−m×n wherein ceiling [x] denotes a minimum integer fromamong integers exceeding ‘x’.
 18. A method for requesting receptionresults for transmitted packets in a mobile communication system, themethod comprising the steps of: consecutively transmitting a number ofpackets (m) while the respective packets are divided into one or morefragmentation packets; and transmitting information about the number ofconsecutively transmitted packets (m) and the number of fragmentationpackets (n).
 19. The method as claimed in claim 18, wherein after theinformation about the number of consecutively transmitted packets (m)and the number of fragmentation packets (n) are transmitted, thefragmentation packets are transmitted.
 20. The method as claimed inclaim 18, wherein after the fragmentation packets are transmitted, theinformation about the number of consecutively transmitted packets (m)and the number of fragmentation packets (n) are transmitted.
 21. Amethod for reporting reception results for received packets in a mobilecommunication system, the method comprising the steps of: consecutivelyreceiving m packets divided into one or more fragmentation packets;receiving information about the number of consecutively received packets(m) and the number of fragmentation packets (n); determining a bitmapconfiguration scheme based on the information about the number ofconsecutively received packets (m) and the number of fragmentationpackets (n); configuring the bitmaps including reception results for therespective fragmentation packets by the determined bitmap configurationscheme; and transmitting the bitmaps.
 22. The method as claimed in claim21, wherein the overall bitmap size for determining the bitmapconfiguration scheme is calculated by the following equation:Overall bitmap size=ceiling[m×n/8]octets wherein ceiling [x] denotes aminimum integer from among integers exceeding ‘x’, m is the number ofconsecutively received packets , and n is the number of fragmentationpackets.
 23. The method as claimed in claim 22, wherein the bitmap sizecorresponding to each of the consecutively received packets isdetermined as n bits.
 24. The method as claimed in claim 23, whereinreception results (k bits) for k fragmentation packets divided from therespective received packets are recorded in a corresponding n-bitbitmap, and ‘0’ is recorded in the remaining bits when k is smaller thann.
 25. The method as claimed in claim 23, wherein out of bitscorresponding to the overall bitmap size, the bits corresponding to thenumber of bits calculated by the following equation arepadding-processed:ceiling[m×n/8]×8−m×n wherein ceiling [x] denotes a minimum integer fromamong integers exceeding ‘x’.
 26. The method as claimed in claim 22,wherein the bitmaps corresponding to the packets are arranged atintervals of n bits within the overall bitmap.
 27. A receiver forconfiguring a Block Acknowledgement (BA) frame in a wirelesscommunication system for acknowledgement of a data transmissi on from atransmitter, the receiver configured to: receive a Block AcknowledgementRequest (BAR) frame in the data transmission from the transmitter;determine an overall size of a bitmap for the BA frame from the BARframe to acknowledge the data transmission; configure the BA frame ofthe response to include the bitmap having the determined overall size;and transmit the configured BA frame to the transmitter, wherein thebitmap of the BA frame includes bits representing reception results ofpackets of the data transmission received from the transmitter.
 28. Thereceiver of claim 27, wherein the overall bitmap size is determined bythe receiver to be:Overall bitmap size=ceiling[m×n/8]octets where ceiling [x] denotes aminimum integer from among integers exceeding ‘x’, the variable ‘m’ is anumber of consecutively received packets and the variable ‘n’ is anumber of fragmentation packets, wherein the variable ‘m’ and thevariable ‘n’ are determined from the BAR frame.
 29. The receiver ofclaim 28, wherein the bitmap of the BA includes a plurality ofindividual bitmaps for the consecutively received packets and a size ofeach individual bitmap corresponding to each of the consecutivelyreceived packets is determined as n bits.
 30. The receiver of claim 29,wherein a number of bits out of the overall bitmap size are paddingbits, the number of padding bits being calculated by the followingequation:ceiling[m×n/8]×8−m×n.
 31. The receiver of claim 27, wherein each bit ofthe bitmap for the block acknowledgement is set as ‘1’ when acorresponding packet is successfully received, and is set as ‘0’ whenreception of the corresponding packet has failed.
 32. The receiver ofclaim 27, wherein information about bitmap size is included in a controlfield of the BAR frame.
 33. The receiver of claim 27, wherein the BARframe includes bitmap size related information used by the receiver indetermining the overall size of the bitmap.